The body includes various passageways such as arteries, other blood vessels, and other body lumens. These passageways, such as a coronary artery, sometimes become constricted or blocked, for example, by plaque or by a tumor. When this occurs, the constricted passageway can be widened in an angioplasty procedure using a balloon catheter, which includes a medical balloon carried by a catheter shaft.
In an angioplasty procedure, the balloon catheter can be used to treat a stenosis, or a narrowing of the body vessel, by collapsing the balloon and delivering it to a region of the vessel that has been narrowed to such a degree that fluid (e.g., blood) flow is restricted. The balloon can be delivered to a target site by passing the catheter shaft over an emplaced guidewire and advancing the catheter to the site. In some cases, the path to the site can be rather tortuous and/or narrow. Upon reaching the site, the balloon is then expanded, e.g., by injecting a fluid into the interior of the balloon. Expanding the balloon can expand the stenosis radially so that the vessel can permit an acceptable rate of fluid flow. After use, the balloon is collapsed, and the catheter is withdrawn.
In some cases, re-stenosis, which is the re-narrowing of the vessel, can occur after an angioplasty procedure. To reduce the occurrence of re-stenosis, the treatment site can be treated with, for example, prolonged balloon inflation, a heated balloon, a cooled balloon, radiation, drugs, and/or a stent.